Mountaineering Mind Games: What role does Altitude really play?

Ever dreamt of climbing to the roof of the world? Visions of standing atop Everest? I recommend reading Jon Krakauer’s Into Thin Air. It will test your commitment to the dream. In Krakauer’s tragically relevant first-hand account of the 1996 disaster on Everest, in which 8 people perished in a blizzard, he discusses at length the games altitude plays with the mind at very high elevations. Krakauer suggests, as many have, that the cause of the high mortality rates during the blizzard that afflicted their expedition were in part due to the madness induced by altitude. With the recent tragedy on the same peak, in which 16 high-altitude workers died in an avalanche, we are reminded of the many dangers of climbing the world’s highest peaks.

Just as calling the Spelling Bee a sport seems to degrade the term sport, calling Mountaineering a sport degrades Mountaineering in its own way.

The term Sport, as applied to Mountaineering, suggests a game and, although there is certainly competition, there are no games when you are atop the world’s highest mountains. Besides the treacherous terrain and other perceptible dangers, invisible dangers creep in close to the heart as negative temperatures and altitude sickness silently, and often slowly, abscond with the lives of many a fit climber every year. Krakauer describes an experience on the mountain, in which his guide told him that there was no more life-saving supplemental oxygen left, when in fact there clearly was. He believes that this encounter was evidence of his guide’s hypoxia-induced madness. Cases of altitude sickness caused by Hypoxia start to be seen above 8,000ft, and Krakauer and his guide would have been above 20,000ft at the time (altitude.org). A mistake like the one Krakauer’s guide made can be extremely dangerous in situations of high risk like theirs. In fact, Krakauer goes on to posit that his guide’s mistake might have been one of the defining factors in the eventual death of some of his group members.

Hypoxia is defined as an insufficient amount of oxygen flowing to vital tissues. It is experienced by mountain climbers due to the low levels of Oxygen in the air at high elevations. This thin air is why mountaineers almost always carry oxygen tanks along with them to the peaks. Altitude sickness describes the resulting symptoms of hypoxia, such as nausea, dizziness, confusion (often described as a sort of madness), clumsiness, and eventually death. The hypoxia at high altitudes is inevitable, even with supplemental oxygen, but the presentation of altitude related symptoms are what are up for debate. This invisible danger has an extreme effect on the brain, but it is also inherently difficult to study in the field. It is difficult enough to get up to the top of these mountains; it is nearly impossible to lug along heavy research and testing equipment, trying to keep it from failing in the frozen temperatures. Thus, there is little agreement in the scientific field about what exactly happens when climbers ascend these great heights. The questions of what exactly happens, when it happens, and if it is permanent are prime questions that beg for data-proven answers. With the ever-rising number of people attempting to summit higher and higher peaks for recreation it is important that we understand what risks lie in wait for them.

Over the years, there has been debate over the cerebral damages caused by high-altitude induced hypoxia. Study after study seems to prove and then disprove serious cognitive impairment. In Merz et al.’s 2013 study of high-altitude climbers they attempted to tackle the question: What will we see if we don’t simply wait for the climbers to get back to see if brain damage has occurred, and instead, test them while they are being directly exposed to the elevation in question? The researchers set out to do away with the many complications and hurdles of an in-field altitude psychological study. They aimed to use a number of different tests to evaluate a group of climbers’ cognitive functioning all along the way as they pushed toward the summit of a high-altitude peak, and compare it to measurements before and after.

One of the ways they made it possible to evaluate cognitive function in the field is by measuring saccadic eye movements: the quick movement of the eyeball in order to redirect vision. These movements have revealed themselves to be a great measurement of all different types of cognitive impairment. The saccadic eye movement tests are conducted by having participants look at a screen and then quickly redirect their eyes to dots as they appear, while scientists track the movement of their pupils. It makes sense that the basic ability of the brain to refocus the eyes from one object to another would only be impaired in cases of clear mental dysfunction, be it permanent or not. People with clear cognitive impairments, such as sleep deprivation or diseases like Alzheimer’s have been shown to have impaired saccadic Eye movements. This particular test also happens to be advantageous because it is relatively easy to bring into the field. The computer based test is not too large to carry along and also acts to rule out many of the human errors that can occur on other tests. This is the first study to use this method of measurement on hypoxic climbers and they certainly got some interesting results.

The researchers studied 32 mountaineers from various backgrounds, none of them professionals, as they pushed toward summiting Muztagh Ata (24,757ft) in western China. The researchers aimed to observe individuals who were comparable to the “hobby” climber (if there is such a thing), rather than studying elite professionals. This way they got more of a sense of how the average climber would fair in hypoxic conditions. There were 3 camps along the way to the summit, each of increasing altitude: C1, C2, and C3, and then the summit respectively. All 32 participants reached the first camp (C1), and though only 17 made it to the summit, they were all tested at whatever their maximum altitude camp was.

Prior to the trip, along the way, and after return to low elevations, the researchers took measurements of cerebral function using some traditional tests, such as self-report symptom questionnaires and measurements of body control, plus the saccadic eye movement tests for all of the climbers. These were taken along with measurements of exactly how hypoxic they were (based on O2 in the blood). The data from all the tests came out in agreement with each other, suggesting that the new attempt to record eye movements as a measure of psychological function was accurate. The addition of saccadic Eye movement testing is significant because it provides a new, highly sensitive, measure for cognitive impairment at altitude rather than relying on some of the older, less sensitive tests. It also provides a data driven test that rules out the observer bias inherent in some older neuropsychological tests, such as tests of body control (ataxia). This test can now be used in future analysis to gain a more consistent measure of impairment.

When all was said and done, and the climbers had climbed up, and then returned to the bottom of the mountain, being tested the whole way, the researchers found no evidence of any cognitive decline in their subjects, despite measured levels of hypoxia in subjects. They concluded that, in fact, hypoxia seemed to be relatively well tolerated as long as the climbers were fit. They didn’t find any long-term brain damage 3 months later (compared to their baseline tests), or even any changes in cognition while the climbers were on the mountain.

Climbers everywhere rejoice!

The researchers found that their participants showed a normal pattern of saccadic eye movements and there were no differences connected to being at various elevations. Basically, any differences that did show up were not related to altitude. On the traditional tests, participants actually improved their performance, which is likely due to a slight retest bias: when the repetition of a specific test produces some inherent improvement in performance. High scores of AMS (Acute Mountain Sickness / Altitude Sickness) symptoms that the researchers took showed a significant correlation with poor scores on the cognitive tests, which suggests that, had there been any altitude related cognitive detriments in their successful mountaineers, they would have shown clearly in the data. However, those who were fit enough to make it to the top didn’t see any of those detriments in this study, or any detriments 3 months later.

The many harrowing accounts of hypoxia’s cognitive detriments have made brain damage a major concern for the families of those who choose to attempt to summit the major peaks. We cannot rule out the killer brain impairment caused by hypoxia based on this one study, but it does keep open the debate surrounding mountaineering as a high-altitude pursuit. Jon Krakauer’s first hand accounts of altitude sickness’ effects during the 1996 Everest disaster provide a haunting reminder that, although we did not see them in this study, scary accounts of altitude induced madness are lurking as a possibility on every summit.

Recently my uncle John (69 year old bad ass) summited Kilimanjaro (19,341 ft) with his buddies (and his retirement money) just for kicks. Yes, my uncle has the muscle tone of a mid-30s fitness guru, but even with almost everything going for him, our first question over email when he returned was still: Any brain damage?! His Reply: